JPH09266480A - Communication connection re-linking method of atm switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a fault recovery by independent dispersion without requiring the centralized management of a network management system in case of a line fault. SOLUTION: Of a switch s1, a PVC control part informed of fault information from a line correspondence part having detected a fault finds a connection- destination switch s2 of the faulty link from adjacent switch connection information for re-linking PVC on the faulty link and makes use of the routing function of SVC for searching for a detour route to the switch s2. The PVC control part of the switch s1 requests an SVC control part to set SVC, and when a connection with the opposite switch s2 is completed by a SVC function, this PVC re-links a connection on the faulty link to the connection where the connection is completed. The switch s1 sends information on the connection completion to the opposite switch s2 after the connection is completed. The opposite switch s2 having received the connection completion information makes a connection on the faulty link by the PVC by re-linking it to the connection where the connection is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a communication connection replacement method that enables independent and distributed failure recovery without the need for centralized management of S. In particular, it relates to an ATM (Asynchronou).
s Transfer Mode) Between terminals of a network, a PVC connection (Pe
rmanent Virtual Connection
n: fixed connection).

[0002]

2. Description of the Related Art A PVC connection is a communication connection between a terminal and a switch and a switch by a PVC registration setting command from a network management system (hereinafter referred to as NMS) that performs maintenance operations such as connection setting change and configuration management of the network. Is a service that fixedly connects the communication connection between the switch and the switch.

When a failure occurs in a line (terminal / switch link, switch / switch link) in which a fixedly connected communication connection is set, communication between terminals cannot be performed. In this case, the switch accommodating the faulty line detects the fault condition and notifies the NMS of which switch in the network has the fault. The NMS that has received the fault notification displays a fault message to notify the network administrator of the abnormality. The network administrator who has detected the abnormality repairs the faulty point or, if there is a bypass route that does not pass through the faulty line, replaces the PVC so that it will go through that route,
This is done by the VC registration setting command.

[0004]

[Problems to be Solved by the Invention] However, NMS
With network monitoring and control using, there is a possibility that failure in the network cannot be recovered when the network administrator is absent, or when an NMS failure occurs, resulting in a significant decrease in network quality or reliability. There is.

The present invention solves the above-mentioned drawbacks of the prior art,
It is an object of the present invention to provide a communication connection replacement method in an ATM switch that is highly reliable against failures by performing network management in a self-sustaining manner.

[0006]

Therefore, the present invention comprises a line interface, a fault detector, a PVC controller which is a fixed connection controller, an SVC controller which is a switching controller, and a network control processor. The line interface notifies the information when the line state changes.

The fault detecting unit reflects the information notified from the line corresponding unit in the line data, and the PVC control unit and the S
Notify the VC control unit of the failure information. The PVC control unit retrieves the registered PVC data corresponding to the faulty line from the fault information, identifies the switch to which the faulty relay link is connected, makes an SVC setting request for selecting the detour route, and notifies the completion of the connection to the SVC. When received from the control unit, the set connection is changed. The SVC control unit
In order to receive the VC setting request, and to perform the optimal routing according to the network state, the address of the connection destination switch is transmitted to the network control processing unit, and the detour route selection request is made.
The call setup message is sent to the corresponding line from the output port number received from the network control processing unit. The network control processing unit collects routing information by sending and receiving a network control monitoring packet to a line connected to another switch. In the ATM switch having the above characteristics, in the case of a line failure, when the network administrator is absent,
The above problem is solved by the following characteristic method using a communication connection replacement method in an ATM switch that autonomously selects a bypass route even when an S failure occurs and replaces the connection.

That is, the communication connection reassignment method in the ATM switch of the present invention comprises means for determining the connection destination switch of the failed relay link from the PVC reattachment adjacent switch connection information provided for each switch, The PVC switch neighboring switch connection information is generated from the network control neighboring switch connection information generated as a result of collecting routing information related to network control.

According to the above method, each switch on the network is provided with the PVC switch neighboring switch connection information generated from the network control neighboring switch connection information generated as a result of routing information collection for network control. In the event of a failure, centralized management of the NMS is not required, and it is possible to recover the failure independently and in a distributed manner.

Therefore, it becomes possible to perform highly reliable PVC replacement when the network manager is absent or when the NMS fails.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention applied to PVC replacement on an ATM network will be described with reference to the drawings. In the present invention, a highly reliable maintenance and operation function for collecting line quality information and the like by using information units used in an ATM network and performing failure management, performance management, etc., and a unique identifier of the information unit are provided. Since it is used effectively, the embodiment in the ATM network is shown.

FIG. 1 shows the configuration of a switch according to an embodiment of the present invention.

Terminals t1, t2, ..., Tn are connected to line 1
, 1n are connected to the line corresponding units 1a, 2a, ..., Na of the switch s1 which is the first switch, respectively. Line corresponding parts 1a, 2a, ...
na is connected to the switch operation unit 2 via the buses 20, 21, ..., 2n, respectively. Switch operation part 2
Are connected to the control device 4, and further to the CPU 5 and the memory 6 in the control device 4 via the internal control bus 50. The switch operating unit 2 includes buses 30, 31, ...
..... n through 3n, line-corresponding units 1b, 2b, ..., N
b. Line support units 1b, 2b, ..., Nb
Are connected to the other ATM switches s2, s3, ...
.., sn connection is made. These other ATM switches
The configuration of 2, s3, ..., Sn is basically the same as that of the switch s1.

The line interface units 1a, 2a, ..., Na and the line interface units 1b, 2b, ..., Nb mainly monitor the state of the accommodated links, and when a failure is detected, the control unit 4 is operated.
The failure detection unit 60 is notified.

The switch operation unit 2 performs an operation of distributing input data, for example, a packet, to an output port to which a destination switch or the like is connected.

The control device 4 comprises a CPU 5 and a memory 6, and controls the switch s1.

FIG. 2 shows a fault detection unit 60, a PVC control unit 61, a network control processing unit 6 in the memory 6 in the switch s1.
2 shows the transfer form of the control signal between the respective areas of the H. 2 and the SVC control unit 63.

The fault detecting section 60 is composed of the line corresponding sections 1a, 2
The failure status notified by a, ..., na is set,
Notify the PVC controller of the occurrence of a failure.

The PVC control unit 61 controls the PVC registration status,
Manage settings and connection status.

The network control processing unit 62 manages the connection state with other switches.

The SVC control unit 63 performs optimum routing according to the state of the network.

A procedure for transferring information between the respective control units on the memory in the switch accompanying the PVC replacement will be described with reference to FIGS. 2 and 6.

The fault detecting unit 60, which has received the link fault notification m1 from the line interface 1b, sets the fault state a2 and transmits the fault notification m2 (→). Failure notification m2
The PVC control unit 61 that has received the
Therefore, the SVC setting request m3 to the SVC control unit 63
To send (→). The SVC control unit 63 that has received the SVC setting request m3 transmits the route selection request m4 to the network control processing unit 62 (→) in order to perform the optimum routing a4. Upon receiving the route selection request m4, the network control processing unit 62 performs detour route selection a5 and sends routing information m5 to the SVC control unit 63 (
→). The SVC control unit 6 that has received the routing information m5
3 makes the SVC connection request a6, the switch s3
A call setup message m6 is sent to (→). SV receiving connection confirmation message m8 from switch s2
The C control unit 63 performs reconnection so as to connect to the VPI / VCI number set in the call acceptance message m7, and clears information on the PVC for which reconnection is completed and information used by the SVC to search for the detour route. Yes (→).

FIG. 3 shows a switch s1 and a switch s1.
This is an example in which a switch s2, a switch s3, and terminals ta and tb having the same configuration as the above are arranged on the network.

The terminal ta is connected to the port # 0 of the switch s1 via the link 100. The port # 1 of the switch s1 is connected to the port # 3 of the switch s2 via the relay link 401, and the port # 2 is connected to the port # 6 of the switch s3 via the relay link 402. The port # 7 of the switch s3 is connected to the port # 4 of the switch s2 via the relay link 403. The port # 5 of the switch s2 is connected to the terminal tb via the link 200.

Between the terminal ta and the terminal tb, P is connected via the switch s1, the relay link 401 and the switch s2.
The VC connection is working normally. This is to connect the communication connection between the terminal ta and the switch s1, the communication connection between the switch s1 and the switch s2 via the relay link 401, and the communication connection between the switch s2 and the terminal tb with the switch s1 and the switch s2. It is realized by.

Here, as shown in FIG. 4, the relay link 40
A communication connection 500 replacement method when a failure occurs in No. 1 will be described with reference to FIGS. 5 and 6. In addition,
Although the failure of the relay link 401 can be detected by both the switch s1 and the switch s2, the case where it is detected by the switch s1 will be described.

When a physical line fault such as a line break or a logical line fault such as modification of data to be communicated occurs in the relay link 401, the relay link 4 of the switch s1.
The line detection unit 1b accommodating 01 performs fault detection a1,
The detection of the link failure is sent to the failure detection unit 60 in the memory 6 of the control device 4 together with the port number accommodating the failure relay link 401 as the link failure notification m1. As an operation when a line failure is detected, for example, there is a method of activating software that causes the control device 4 to perform a processing procedure when a failure occurs, based on the failure information detected by the line corresponding unit 1b in terms of hardware. .

In the fault detecting section 60, the link fault notification m1
7 is received, the fault state setting a2 is performed in the data area of the memory (for example, RAM) in which the line state data shown in FIG. 7 is searched by the port number included in the link fault notification m1. As a result, the change in the line status can be reflected in the line status data. As a method of setting the failure state, for example, the notified port number is used as an address of the memory 6, and the line state is set in the data area corresponding to this address:
It is realized by storing each state of normal (for example, writing 1) and line state: abnormal (for example writing 0). Further, in order to automatically replace the PVC that has become incapable of communication due to the failure, the occurrence of the failure is transmitted to the PVC control unit 61 as a failure notification m2 together with the port number.

The PVC control unit 61 which has received the failure notification m2
Performs the PVC replacement a3 set on the line of the port number notified by the failure notification m2. First,
Registered PVC corresponding to line by port number in Fig. 8
Line-corresponding registered PVC showing data (VPI / VCI)
VPI of PVC which searched data and port number matched
/ VCI. Then, the switch of the connection destination of the relay link having the fault at the port number notified by the fault notification m2 is connected between the address of the adjacent switch, the output port number of the adjacent switch, and the output port number of the own switch port of FIG. It is obtained from the PVC replacement adjacent switch connection information indicating the state (in this case, the switch s2), and is sent to the SVC control unit 63 to investigate whether or not there is a detour route that can be connected to the switch s2 other than the failed relay link. On the other hand, the SVC setting request m3 is transmitted with the address of the switch s2 as the destination address. The PVC replacement adjacent switch connection information is collected, for example, by a packet that each switch on the network transmits / receives to / from an adjacent switch in a constant cycle.

The SVC control unit 63 switches the caller
1, the protocol identifier, call number, message type, message length, ATM traffic identifier information element, broadband transmission capability information element, destination address information element, destination subaddress information element A call setup message m6 including an address information element, a calling subaddress information element, a connection identifier information element, a QoS parameter information element, etc. (for example, SET
UP message) to the switch s3. The calling subaddress information element in the call setup message m6 includes
The extracted VPI / VCI and the port number notified of the failure are set.

When the SVC control unit 63 receives the SVC setting request m3 in which the address of the switch s2 is set as the destination address, the optimum routing a4 according to the network state.
Switch s2 to the network control processing unit 62 to perform
The route selection request m4 is transmitted using the address of the destination address as the destination address.

Upon receiving the route selection request m4, the network control processing unit 62 determines whether or not there is a route that can be routed to the destination address (address of the switch s2) included in the route selection request m4. If the destination table (address of the switch s2) is found in the routing table by searching the routing table showing the output port number for the target address, the output port number of the switch s1 accommodating the relay link corresponding to the destination address is set. Obtained and returned to the SVC control unit 63.

In the SVC control unit 63, the SVC connection request a
6, the call setup message m6 is sent to the line corresponding to the output port number returned from the network control processing unit 62, that is, the relay link 402 connected to the output port # 2 of the switch s1.
1 for sending a call and simultaneously using it for the call setup message m6.
It is set in the call number / fault VPI / VCI correspondence table shown in FIG. The call number is a number for identifying a call assigned to each call, and the call number-faulty VPI / VCI correspondence table shows the port number of the faulty PVC corresponding to the call number and the faulty VPI / VCI. It shows a history.

The switch s3 having received the call setup message m6 sent to the relay link 402 performs the SVC connection process a7 for sending the call setup message m7 to the relay link 403 because the destination address is the switch s2.

The switch s2 having received the call setup message m6 transmitted to the relay link 403 performs the SVC connection processing a9 and terminates the call setup message because the destination address is the switch s2. Call setup message m
It is searched from the connection information of the neighboring switch for PVC replacement whether the calling address stored in 6 is the address of the switch adjacent to the switch s2. If it is the address of the neighboring switch, in the terminated call setup message m6. The information (port number of the switch s1 and VPI / VCI) set in the outgoing sub-address information element of is extracted, and the address of the switch s1 and the port number of the switch s1 are connected from the PVC replacement adjacent switch connection information. The output port number of the switch s2 that is being operated is obtained.

The outgoing sub-address information element is conventionally an information element for identifying a plurality of terminals subordinate to a main terminal for communication, but in the present invention, this area is set as a failure port number of a switch in which a failure is detected. , And impaired VPI /
It is used for VCI setting.

The PVC switch adjacent switch connection information is generated from the network control adjacent switch connection information shown in FIGS. 11 and 17 which is generated as a result of routing information collection in the network control processing. The network control adjacent switch connection information is
The connection state of the address of the adjacent switch, the output port number of the adjacent switch, and the output port number of the own switch port is shown, and a monitoring packet (for example, Hello
It is collected by sending and receiving packets) at regular intervals.
However, the network control adjacent switch connection information is cleared when the abnormality is detected in the monitoring packet, assuming that the adjacent information of the relevant port (adjacent switch address, output port number) is not connected, but for PVC replacement. The adjacent switch connection information is not cleared but updated when the abnormality detection port is restored and new adjacent information is acquired. This is because the network control adjacent switch connection information is intended to always collect the latest adjacent information, and the PVC replacement adjacent switch connection information includes the adjacent information including a failure to replace the PVC when a failure is detected. This is for the purpose of collecting the history of.

An example of operation for collecting network control adjacent switch connection information will be described with reference to FIG. When communication is performed between the switch sw-a and the switch sw-b, the switch sw-
As the information of the own device, a transmits a monitoring packet having an address (sw-a) and a port (# 1) to an adjacent switch sw-b. Switch sw- that received this
In b, each piece of information of the address: sw-a, the adjacent switch port: # 1, and the own switch port: # 0 is held as the network control adjacent switch connection information, and the switch sw
Similarly, from -b, the address (sw
-B), the monitor packet equipped with the port (# 0) is sent to the adjacent switch sw-a. In the switch sw-a which receives this, as the network control adjacent switch connection information, the address: sw-b, the adjacent switch port: # 0,
And information about its own switch port: # 1.

The switch s2 having received the call setting message m6 performs the SVC connection processing a9, and after the VPI / VCI for connection to the bypass route is established, the call acceptance processing a9.
10 and call acceptance message m8 (for example, CALL
_PROC message). Further, the connection availability judgment a11 is performed, and if the connection is possible, a connection confirmation message m8 (for example, CONN message) is returned.

The call acceptance message m7 and the connection confirmation message m8 returned from the switch s2 are the route (relay link 40) through which the call setup message m6 has been transferred.
3, the switch s3, and the relay link 402), and is transferred to the switch s1 that is the transmission source.

When the connection confirmation message m8 is returned as a result of the SVC connection request a6 by the switch s1,
The call number in the connection confirmation message m8 is the call number-fault V
Search the PI / VCI correspondence table data to find the fault port number,
And VPI / VCI are extracted, and the VPI /
The connection replacement a12 is performed so that the communication connection between the terminal ta connected to the VCI and the switch s1 is connected to the VPI / VCI number set in the call acceptance message received from the relay link 402, and the PVC that has completed the replacement is connected. Related information and line-corresponding PVC data and call number-failed VPI / for the call number when the SVC is used to search the replacement route.
Clear the VCI correspondence table data. Terminal at this point
A communication connection is established between the switch s1 and the switch s1, between the switches s1 and s3, and between the switches s3 and s2.

The switch s1 sends a notification message m9 (for example, NOTIF) to the route for which the connection completion processing a13 is performed.
(Y message) and relay link 40
2, switch s3, and relay link 403 to switch s2. As shown in FIG. 20, the notification message includes a protocol identifier, a call number, a message type, a message length, and a notification identifier information element.

The switch s that has received the notification message m9
At 2, the faulty VPI / VCI corresponding to the call number of the notification message m9 is obtained from the call number-faulty VPI / VCI correspondence table, and the communication connection between the terminal B and the switch s2 connected to the VPI / VCI of the faulty PVC is established. , The relay link 2 set by the call number notified by the notification message m9
Replace PVC to connect 3 communication connections. That is, the call number of the notification message m9 is the call number-
The failure VPI / VCI correspondence table is searched to find the port number of the failure PVC and the failure VPI / VCI.

The communication connection between the switch s2 and the terminal tb, which has been connected to the requested faulty PVC port number, is set so as to connect with the VPI / VCI of the port of the user connection of the call number notified by the notification message m9.
Replace VC. Corresponding to the registered PVC data corresponding to the line showing the PVC data corresponding to the port number of FIG. 14 when the SVC is used to search the information of the PVC for which the replacement is completed and the route of the replacement, and the call number of FIG. Faulty PVC port number and faulty VPI
Clears the call number / failure VPI / VCI correspondence table data indicating / VCI. At this point, the terminal tb and the switch s2
The communication connection between them is established, and the replacement of PVC is completed.

According to the above procedure, the PVC replacement is completed and communication is possible between the terminal ta and the terminal tb by the detour route passing through the switch s1, the relay link 402, the switch s3, the relay link 403, and the switch s2.

By the above-mentioned method, it is possible to utilize the characteristics of ATM and flexibly perform centralized management of NMS at the time of line failure, and to perform failure recovery independently and in a distributed manner.

Although the above description is for the switch s1, the same processing is performed for other switches such as the switch s2.

The present invention is not limited to the above embodiment. For example, in a network composed of more switches than in the above embodiment, there may be a plurality of detour routes, but the present invention implements information on the priority of each line, fixed connection and network control adjacent switch connection information, etc. It is possible to deal with this by providing each switch on the network with a configuration for selecting an optimal detour route by using each information used in the example as switching information.

[0050]

As described above, according to the present invention, the fixed connection replacement adjacent switch connection information generated from the network control adjacent switch connection information generated as a result of routing information collection related to network control is transmitted to the network. By providing each of the above switches, it is possible to perform self-distributed failure recovery without the need for centralized management of the network management system in the event of a line failure. Further, it becomes possible to apply an identifier of an information unit used in the ATM network and a highly reliable maintenance operation function.

[Brief description of drawings]

FIG. 1 is a block diagram of an ATM switch according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a processing unit on a controller memory according to the embodiment of the present invention.

FIG. 3 is a network configuration diagram in the case where a PVC is set up between the terminals A and B via the relay link 401 in the embodiment of the present invention.

FIG. 4 is a network configuration diagram when a failure occurs in the relay link 401 according to the embodiment of this invention.

FIG. 5 is a network configuration diagram when a PVC is replaced in response to a failure of the relay link 401 according to the embodiment of this invention.

FIG. 6 is a sequence according to the embodiment of the present invention.

FIG. 7 is a diagram showing line state data on a memory of the control device of the switch s1 according to the embodiment of the present invention.

FIG. 8 is a diagram showing line-registered registered PVC data on a memory of the control device of the switch s1 according to the embodiment of the present invention.

FIG. 9 is a call number / fault VPI / VCI correspondence table on the memory of the controller of the switch s1 according to the embodiment of the present invention.

FIG. 10 is a routing table on a memory of the control device for the switch s1 according to the embodiment of the present invention.

FIG. 11 is a diagram showing network control adjacent switch connection information on a memory of the controller of the switch s1 according to the embodiment of the present invention.

FIG. 12 is a diagram showing PVC reconnection adjacent switch connection information on a memory of the control device for the switch s1 according to the embodiment of the present invention.

FIG. 13 is a diagram showing line state data on a memory of the control device of the switch s2 in the example of the present invention.

FIG. 14 is a diagram showing line-registered registered PVC data on a memory of the controller of the switch s2 according to the embodiment of the present invention.

FIG. 15 is a call number / fault VPI / VCI correspondence table on the memory of the controller of the switch s2 in the embodiment of the present invention.

FIG. 16 is a routing table on a memory of the control device for the switch s2 according to the embodiment of the present invention.

FIG. 17 is a diagram showing network control adjacent switch connection information on a memory of the controller of the switch s2 in the embodiment of the present invention.

FIG. 18 is a diagram showing PVC reconnection adjacent switch connection information on the memory of the control device for the switch s2 in the example of the present invention.

FIG. 19 is a call setup message structure according to an embodiment of the present invention.

FIG. 20 is a notification message structure according to an embodiment of the present invention.

FIG. 21 is a diagram showing neighbor switch connection information collection in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Switch, 2 ... Switch operation part, 1a ... Line correspondence part, 2a ... Line correspondence part, na ... Line correspondence part, 1b ... Line correspondence part, 2b ... Line correspondence part, nb ... Line correspondence part, 4 ... Control device 5, ... CPU, 6 ... Memory, 60 ... Failure detection unit,
61 ... PVC control unit, 62 ... Network control processing unit, 63 ... SV
C control unit.

Claims (6)

[Claims] 1. A line interface for notifying information of a change in the monitored line status, a fault detector for reflecting the information in the line data and notifying fault information, and the fault. It is set when the registered fixed connection data corresponding to the faulty line is searched from the information, the switch to which the faulty relay link is connected is specified, the exchange setting request for selecting the detour route is made, and the notification of the connection completion is received. A fixed connection control unit that reconnects the existing connection, receives the exchange setting request, sends the address of the connection destination switch to make a detour route selection request, and sends a call setting message to the selected line, It receives a call acceptance message and a connection confirmation message as its response from the connection destination switch, and receives the detour route selection request and the exchange control unit that notifies the completion of the connection. ATM switches and sends a network control monitoring packet to the line that is connected to another switch, also characterized in that it comprises a network control processor for collecting routing information by receiving. 2. The ATM switch according to claim 1, further comprising means for accumulating connection information of adjacent switch for fixed connection replacement for identifying a connection destination switch of the relay link having a failure. 3. An ATM network in which a plurality of ATM switches according to claim 1 are connected. 4. The first switch connected to the failed relay link detects a failure of the relay link, sets and notifies link failure information, and establishes a communication connection preset from the link failure information. The data is searched for, the second switch connected to the relay link and facing the first switch is selected, the detour route is selected, the data used in the call setup message is set, and the detour route is selected. When the call acceptance message and the connection confirmation message are received, the communication connection between the terminals connected to the first switch is set to the VPI / VCI number set in the call acceptance message. The notification message to notify the second switch that the connection has been changed. The second switch connected to the relay link, when the destination address of the call setup message is the second switch, terminates the call setup message and sends the call setup message. The port number of the second switch that is connected to the port number of the first switch that has been performed, the call acceptance message and the connection confirmation message is transmitted, and when the notification message is received, the second A communication connection replacement method in an ATM switch, wherein a faulty communication connection between terminals connected to the switch is replaced with a communication connection set by the call number notified by the notification message. 5. The communication connection in an ATM switch according to claim 4, wherein the connection destination switch of the failed relay link is specified from the fixed switch replacement adjacent switch connection information provided in the own switch. How to refill. 6. The ATM switch according to claim 5, wherein the fixed connection replacement adjacent switch connection information is created from network control adjacent switch connection information generated as a result of routing information collection related to network control. Reconnection method for communication connection in.